Method for decreasing sebum production

ABSTRACT

The present invention is directed to the topical application of the malonamide ACAT inhibitors described by Formula I. Other aspects of the invention are directed to topical formulations of these diamides, their use to treat sebaceous gland disorders and their use to alleviate oily skin.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application60/509,984 filed Oct. 9, 2003.

FIELD OF THE INVENTION

The present invention is directed to the topical application of a classof diamide ACAT inhibitors. Other aspects of the invention are directedto topical formulations of these diamides, their use to treat sebaceousgland disorders and their use to alleviate oily skin.

BACKGROUND OF THE INVENTION

Human skin is composed of three primary layers, the stratum corneum, theepidermis, and the dermis. The outer layer is the stratum corneum. Itsprimary function is to serve as a barrier to the external environment.Lipids are secreted to the surface of the stratum corneum. These lipidsdecrease the stratum corneum's water permeability. Sebum typicallyconstitutes 95% of these lipids. Abramovits et al, Dermatologic Clinics,Vol 18, Number 4, October 2000.

Sebum is produced in the sebaceous glands. These glands are present overmost of the surface of the body. The highest concentration of theseglands occurs on the scalp, the forehead and the face. Despite theimportant physiological role that sebum plays, many individualsexperience excess sebum production, especially in the facial area.Excess sebum is associated with an increased incidence of acne. Even inindividuals without acne, sebum can make the skin look greasy,decreasing its attractiveness. Abramovits et al, supra.

Current treatments for excess sebum are less than optimal. Accutane(isotretinoin) reduces sebum secretion by up to 90%. However,isotretinoin is associated with a number of serious side effects. Itcauses serious birth defects and is contraindicated in women ofchildbearing age. Thus, isotretinoin is only utilized for severe acne.It is inappropriate to use this drug merely as a cosmetic aid.

Acyl CoA cholesterol acyl transferase (ACAT) inhibitors were initiallyevaluated to treat elevated cholesterol. U.S. Pat. No. 6,133,326discloses that ACAT inhibitors also reduce the secretion of sebum. Whilethe '326 patent is a valuable contribution to the art, such treatmentsare not commercially available at the present time. Currently, the mostpractical means of alleviating excess sebum is frequent washings. Thus,a need exists in the art for new treatments that will reduce thesecretion of sebum by the sebaceous glands.

SUMMARY OF THE INVENTION

A new method for decreasing the secretion of sebum, by the sebaceousglands, has been discovered. A class of ACAT inhibitors that exhibitsuperior activity in the inhibition of sebum secretion has beendiscovered. These ACAT inhibitors may be represented by Formula I:

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or —(CH₂)_(q)-M; pis represented by an integer from 1 to 4; R⁴ is represented by asubstituent selected from the group consisting of hydrogen, C₁₋₆ alkyl,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alkyl; Ph is represented by a phenylring which may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring, containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; a pharmaceutically acceptable salt thereof, or aprodrug thereof.

The compounds of Formula I may be administered to a patient to decreasethe amount of sebum secreted by their sebaceous glands. Typically, thecompounds will be administered topically to the areas exhibiting excesssebum production. Decreasing sebum secretion will alleviate a number ofdermatological disorders and cosmetic complaints. These conditionsinclude oily skin, oily hair, shiny skin, acne, and seborrheicdermatits.

The invention is also directed to pharmaceutical compositions containingat least one of the compounds of Formula I in admixture with a carriersuitable for topical administration. In a further embodiment, theinvention is directed to an article of manufacture containing a compoundof Formula I, packaged for retail distribution, in association withinstructions advising the consumer on how to use the compound toalleviate a condition associated with excess sebum production. Anadditional embodiment is directed to the use of a compound of Formula Ias a diagnostic agent to detect inappropriate sebum production. Otheraspects of the invention are directed to the use of a compound ofFormula I in the manufacture of a medicament for seborrhea.

DETAILED DESCRIPTION OF THE INVENTION

The headings within this document are only being utilized expedite itsreview by the reader. They should not be construed as limiting theinvention or claims in any manner.

A) Definitions and Exemplification

As used throughout this application, including the claims, the followingterms have the meanings defined below, unless specifically indicatedotherwise. The plural and singular should be treated as interchangeable,other than the indication of number:

-   -   a. “C₁-C₆ alkyl” refers to a branched or straight chained alkyl        group containing from 1 to 6 carbon atoms, such as methyl,        ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl,        isopentyl, n-hexyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, etc.    -   b. “C₁-C₆ alkoxy” refers to a straight or branched chain alkoxy        group containing from 1 to 6 carbon atoms, such as methoxy,        ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentoxy,        n-hexyloxy, etc.    -   c. “halogen” refers to a chlorine, fluorine or bromine atom.    -   d. “optionally substituted phenyl” refers to a phenyl (—C₆H₅)        which may be substituted with up to 3 substituents, each        substituent is independently selected from the group consisting        of C₁₋₆ alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl,        trifluoromethoxy, cyano, NR⁵R⁶, or SR⁷. These substituents may        be the same or different and may be located at any of the ortho,        meta, or para positions.    -   e. “heteroaryl” refers to aromatic ring having a single        heteroatom selected from oxygen, nitrogen and sulfur. More        specifically, it refers to a 5-, or 6-, membered ring containing        1 nitrogen atom, 1 oxygen atom, or 1 sulfur atom. The 5-membered        ring has 2 double bonds and the 6-membered ring has 3 double        bonds. Examples of such heteroaryl ring systems include, but is        not limited to pyrrolyl, furanyl, thiophenyl, and pyridinyl.    -   f. “pharmaceutically acceptable salts” is intended to refer to        either pharmaceutically acceptable acid addition salts” or        “pharmaceutically acceptable basic addition salts” depending        upon actual structure of the compound.    -   g. “pharmaceutically acceptable acid addition salts” is intended        to apply to any non-toxic organic or inorganic acid addition        salt of the base compounds represented by Formula I or any of        its intermediates. Illustrative inorganic acids which form        suitable salts include hydrochloric, hydrobromic, sulphuric, and        phosphoric acid and acid metal salts such as sodium monohydrogen        orthophosphate, and potassium hydrogen sulfate. Illustrative        organic acids, which form suitable salts include the mono-, di-,        and tricarboxylic acids. Illustrative of such acids are for        example, acetic, glycolic, lactic, pyruvic, malonic, succinic,        glutaric, fumaric, malic, tartaric, citric, ascorbic, maleic,        hydroxymaleic, benzoic, hydroxy-benzoic, phenylacetic, cinnamic,        salicylic, 2-phenoxybenzoic, p-toluenesulfonic acid, and        sulfonic acids such as methane sulfonic acid and 2-hydroxyethane        sulfonic acid. Such salts can exist in either a hydrated or        substantially anhydrous form. In general, the acid addition        salts of these compounds are soluble in water and various        hydrophilic organic solvents, and which in comparison to their        free base forms, generally demonstrate higher melting points.    -   h. “pharmaceutically acceptable basic addition salts” is        intended to apply to any non-toxic organic or inorganic basic        addition salts of the compounds represented by Formula I, or any        of its intermediates. Illustrative bases which form suitable        salts include alkali metal or alkaline-earth metal hydroxides        such as sodium, potassium, calcium, magnesium, or barium        hydroxides; ammonia, and aliphatic, alicyclic, or aromatic        organic amines such as methylamine, dimethylamine,        trimethylamine, and picoline.    -   i. “prodrug” refers to compounds that are rapidly transformed in        vivo to yield the parent compound of the above formulas, for        example, by hydrolysis in blood. A thorough discussion is        provided in T. Higuchi and V. Stella, “Pro-drugs as Novel        Delivery Systems,” Vol. 14 of the A.C.S. Symposium Series, and        in Bioreversible Carriers in Drug Design, ed. Edward B. Roche,        American Pharmaceutical Association and Pergamon Press, 1987,        both of which are incorporated herein by reference.    -   j. “compound of Formula I”, “compounds of the invention” and        “compounds” are used interchangeably throughout the application        and should be treated as synonoms.    -   k. “patient” refers to warm blooded animals such as, for        example, guinea pigs, mice, rats, gerbils, cats, rabbits, dogs,        monkeys, chimpanzees, and humans.    -   l. “treat” refers to the ability of the compounds to either        relieve, alleviate, or slow the progression of the patient's        disease (or condition) or any tissue damage associated with the        disease.

Some of the compounds of Formula I will exist as optical isomers. Anyreference in this application to one of the compounds represented byFormula I is meant to encompass either a specific optical isomer or amixture of optical isomers (unless it is expressly excluded). Thespecific optical isomers can be separated and recovered by techniquesknown in the art such as chromatography on chiral stationary phases orresolution via chiral salt formation and subsequent separation byselective crystallization. Alternatively utilization of a specificoptical isomer as the starting material will produce the correspondingisomer as the final product.

In addition, the compounds of the present invention can exist inunsolvated as well as solvated forms with pharmaceutically acceptablesolvents such as water, ethanol, and the like. In general, the solvatedforms are considered equivalent to the unsolvated forms for the purposesof the present invention.

Any reference in this application to a compound of Formula I, isintended to cover the compounds individually, as mixtures, as salts, assolvates or any combination thereof.

All of the compounds of Formula I have at least two phenyl rings, asdepicted immediately below:

Ring A may be unsubstituted, or it may be substituted with one or twosubstituents as defined by R¹ and R². R¹ and R² may be represented byidentical substituents, or different substituents. In one embodiment, R¹and R² are each represented by isopropyl moieties and are both locatedat the ortho positions of the phenyl ring.

Ring B may also be optionally substituted, as listed for R⁴. R⁴ mayrepresent up to 3 substituents, other than hydrogen, as described above.These substituents may be located at any of the ortho, meta, or parapositions.

R³ may also be represented may a phenyl ring or a phenylalkylene moiety.Any such phenyl ring may also be substituted with up to 3 substituents,as described above. They may be located at any of the ortho, meta, orpara positions.

R³ may also be represented by a heteroaryl ring or by aheteroarylalkylene moiety. The heteroaryl ring may be attached to theindicated nitrogen atom by any carbon atom of the heteroaryl ring.Likewise, if q is 1,2,3, or 4, then the heteroaryl ring may be bonded tothe alkylene moiety via any of its carbon atoms.

In a further embodiment of the invention, Formula IA exemplifies asubgenus of Formula I, particularly useful for topical application.

In Formula IA, R¹ and R² are each isopropyl (ortho), p is 1 and X ismethylene, as exemplified above; R³ is represented by C₁₋₆ alkyl orheteroaryl, (more typically isopropyl, or pyridyl) and R⁴ is as definedin Formula I.

More specific examples of compounds of Formula Ia include:

-   -   a) N-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide;    -   b)        N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide        and;    -   c)        N-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.

B) Synthesis

The compounds of Formula I have previously been described in theliterature. The reader's attention is directed to European PatentApplication Number 0 433 662, which is hereby incorporated by reference.The '662 application discloses that the compounds of Formula I haveacyl-coenzyme A cholesterol acyltransferase (ACAT) inhibitory activity.The '662 application discloses that these compounds can be used to lowerelevated cholesterol levels and to treat atherosclerosis. The '662application does not disclose using these compounds to decrease sebumsecretion.

The '662 application discloses how to prepare the compounds of FormulaI. The reader's attention is directed to pages 7-20 where methods forsynthesizing these compounds are described. Methods for preparingpharmaceutically acceptable salts of these compounds are described onpage 6 of the specification.

C) Medical and Cosmetic Uses

Inhibition of acyl-CoA cholesterol acyl transferase (ACAT) blocks theesterification of free cholesterol-to-cholesterol esters. Cholesterolesters are the primary transportation and storage form of cholesterol inanimals. In the intestines, ACAT inhibitors have been shown to inhibitthe absorption of cholesterol from the gut. In the liver, inhibition ofACAT has been shown to decrease the formation and secretion ofcholesterol-containing lipoproteins by decreasing the cholesterol estermass of the lipoprotein core. For these reasons, ACAT inhibitors havepreviously been evaluated as a means to lower serum cholesterol levels.

Dermal sebaceous glands are holocrine glands that secrete a mixture oflipids known as sebum. Sebum is composed of triglycerides, wax, sterolesters and squalene. There is considerable variation in the compositionof human sebum based on individual variables such as age, sex, diet, anddisease. Sebum is produced in the acinar cells of sebaceous glands,accumulates as those cells age and migrates towards the center of thegland. At maturation, the acinar cells lyse and release sebum into thelumenal duct, from which the sebum is secreted.

Formation of sebum is regulated by a variety of hormones that actprimarily to regulate the rate of lipid metabolism. Waxes and sterolsare converted, within acinar cells, to a stable ester form for storagevia the activity of a variety of acyl and fatty acid transferases. Theseesters are then stored in lipid droplets within the acinar cells priorto release.

The compounds of formula I block the conversion of freecholesterol-to-cholesterol ester, leading to increased levels of freecholesterol within the acinar cells. While the cellular mechanism is notfully understood at the present time, the acinar cells produce lesssebum when contacted with an ACAT inhibitor.

Thus, the compounds of formula I inhibit the secretion of sebum and thusreduce the amount of sebum on the surface of the skin. The compounds canbe used to treat a variety of dermal diseases such as acne or seborrheicdermatitis.

In addition to treating diseases associated with excess sebumproduction, the compounds can also be used to achieve a cosmetic effect.Some consumers believe that they are afflicted with overactive sebaceousglands. They feel that their skin is oily and thus unattractive. Theseindividuals can utilize the compounds of Formula I to decrease theamount of sebum on their skin. Decreasing the secretion of sebum willalleviate oily skin in individuals afflicted with such conditions.

In order to exhibit the biological effects described above, thecompounds need to be administered in a quantity sufficient to inhibitproduction and/or secretion of sebum by the sebaceous glands and acinarcells. This amount can vary depending upon the particulardisease/condition being treated, the severity of the patient'sdisease/condition, the patient, the particular compound beingadministered, the route of administration, and the presence of otherunderlying disease states within the patient, etc. When administeredsystemically, the compounds typically exhibit their effect at a dosagerange of from about 0.1 mg/kg/day to about 100 mg/kg/day for any of thediseases or conditions listed above. Repetitive daily administration maybe desirable and will vary according to the conditions outlined above.

The compounds of the present invention may be administered by a varietyof routes. They are effective if administered orally. The compounds mayalso be administered parenterally (i.e. subcutaneously, intravenously,intramuscularly, intraperitoneally, or intrathecally), rectally, ortopically.

In a typical embodiment, the compounds are administered topically.Topical administration is especially appropriate for acne and forcosmetic indications. The compound will be applied to those areas of theskin afflicted with excess sebum production. The dose will vary, but asa general guideline, the compound will be present in a dermatologicallyacceptable carrier in an amount of from 0.01 to 10 w/w % and thedermatological preparation will be applied to the affected area from 1to 4 times daily. “Dermatologically acceptable” refers to a carrierwhich may be applied to the skin, hair or scalp, and which will allowthe drug to diffuse to the site of action. (i.e. the sebaceous glandsand/or the acinar cells).

D) Co-Administration

In a further embodiment of the invention, the compounds of Formula I canbe co-administered with other compounds to further enhance theiractivity, or to minimize potential side effects. For example,antibiotics, such as tetracycline and clindamycin, have been used toalleviate acne. The antibiotic eradicates the microorganism,Propionbacterium acnes, leading to a reduction in the patient's acne.The compounds of Formula I can be co-administered with any antibioticsuitable for the treatment of acne.

Retinoids, such as isotretinoin, have been shown to decrease sebumproduction and are used to treat acne. These retinoids can beco-administered with a compound of Formula I in order to decrease sebumproduction and/or to treat acne.

Estrogen and progesterone have each been shown to decrease sebumproduction. These compounds, or any synthetic agonist of the estrogen orprogesterone receptor, may be co-administered with a compound of formulaI in order to decrease sebum production.

Anti-androgens have been shown to decrease sebum secretion.Anti-androgens can work by a number of different mechanisms. Forexample, some compounds block the conversion of testosterone to5-α-dihydrotestosterone, which is responsible for the biological effectin many tissues. 5-Alpha-reductase inhibitors, such as finasteride, havebeen shown to decrease sebum production. Finasteride is commerciallyavailable from Merck under the trade name Propecia®. Examples of other5-α-reductase inhibitors include dutasteride (Glaxo Smithkline). Otheranti-androgens are antagonists of the androgen receptor. For example,androgen antagonists, such as flutamide, have been reported to decreasesebum production. Such compounds can be co-administered with thecompounds of Formula I to decrease sebum production.

As used in this application, co-administered refers to administering acompound of Formula I with a second medicinal, typically having adiffering mechanism of action, using a dosing regimen that promotes thedesired result. This can refer to simultaneous dosing, dosing atdifferent times during a single day, or even dosing on different days.The compounds can be administered separately or can be combined into asingle formulation. Techniques for preparing such formulations aredescribed below.

E. Cosmetic and Pharmaceutical Formulations

If desired, the compounds can be administered directly without anycarrier. However, to ease administration, they will typically beformulated into pharmaceutical carriers

For oral administration, the compounds can be formulated into solid orliquid preparations such as capsules, pills, tablets, lozenges, melts,powders, suspensions, or emulsions. Solid unit dosage forms can becapsules of the ordinary gelatin type containing, for example,surfactants, lubricants and inert fillers such as lactose, sucrose, andcornstarch or they can be sustained release preparations.

In another embodiment, the compounds can be tableted with conventionaltablet bases such as lactose, sucrose, and cornstarch in combinationwith binders, such as acacia, cornstarch, or gelatin, disintegratingagents such as potato starch or alginic acid, and a lubricant such asstearic acid or magnesium stearate. Liquid preparations are prepared bydissolving the active ingredient in an aqueous or non-aqueouspharmaceutically acceptable solvent, which may also contain suspendingagents, sweetening agents, flavoring agents, and preservative agents asare known in the art.

For parenteral administration the compounds may be dissolved in aphysiologically acceptable pharmaceutical carrier and administered aseither a solution or a suspension. Illustrative of suitablepharmaceutical carriers are water, saline, dextrose solutions, fructosesolutions, ethanol, or oils of animal, vegetative, or synthetic origin.The pharmaceutical carrier may also contain preservatives, buffers,etc., as are known in the art. When the compounds are being administeredintrathecally, they may also be dissolved in cerebrospinal fluid as isknown in the art.

Typically however, the compounds will be incorporated into formulationssuitable for topical administration. Any of the topical formulationsknown in the art may be used. Examples of such topical formulationsinclude lotions, sprays, creams, ointments, salves, gels, etc. Actualmethods for preparing topical formulations are known or apparent tothose skilled in the art, and are described in detail in Remington'sPharmaceutical Sciences, 1990 (supra); and Pharmaceutical Dosage Formsand Drug Delivery Systems, 6th ed., Williams & Wilkins (1995).

In a further embodiment, the formulations described above may bepackaged for retail distribution (i.e., a kit or article ofmanufacture). The package will contain instructions advising the patienthow to use the product to alleviate conditions such as acne, oily skin,etc. Such instructions may be printed on the box, may be a separateleaflet or printed on the side of the container holding the formulation,etc.

The compounds of Formula I may also be admixed with any inert carrierand utilized in laboratory assays in order to determine theconcentration of the compounds within the serum, urine, etc., of thepatient as is known in the art. The compounds may also be used as aresearch tool.

While the invention has been described in connection with specificembodiments thereof, it will be understood that it is capable of furthermodifications and this application is intended to cover any variations,uses, or adaptations of the invention following, in general, theprinciples of the invention and including such departures from thepresent disclosure as come within known or customary practice within theart to which the invention. The following examples and biological dataare being presented in order to further illustrate the invention. Thisdisclosure should not be construed as limiting the invention in anymanner.

EXAMPLE I

Luderschmidt et al describes an animal model for testing whethercompounds are capable of modulating sebum secretion. Arch. Derm. Res.258, 185-191 (1977). This model uses Syrian hamsters, whose ears containsebaceous glands. Compounds can be administered to these animals todetermine if a test agent is capable of modulating sebum production Aseries of compounds known to inhibit ACAT were screened using methodsanalogous to those of Luderschmidt et al. Table IA shows the resultsobtained with selected diamides encompassed by Formula I above. Table IBshows the results obtained with a series of diamides not encompassed byFormula I. Formula IC shows the results obtained with other potent ACATinhibitors that are not diamidess.

Tables IA-IC also reports the affinity of the compound for rat ACAT,measured as an IC₅₀. These values were determined by measuring theACAT-mediated transfer of tritiated oleic acid from acyl-CoA tocholesterol to give labeled cholesteryl oleate. The source of ACATactivity was homogenates of rat intestinal tissue. Predeterminedconcentrations of: 1) intestinal homogenate containing endogenouscholesterol, 2) test compound, and 3) [1-¹⁴C] oleolyl-CoA were contactedfor a predetermined time. The reaction was quenched and the results weredetermined by thin layer chromatography. Analogous assays using rabbitintestine were described by Roth et al in J. Med Chem.35:1609-1617(1992).

Testing for sebum inhibition was carried out in the following manner.Male Syrian hamsters aged 9 to 10 weeks were introduced into thelaboratory environment and acclimated for 2 weeks prior to use in thestudy. Each group consisted of 5 animals and were run in parallel withvehicle and positive controls. Prior to administration, 10 mg of eachcompound was dissolved in 1 mL of Universal solvent (ethanol/propyleneglycol (70/30% v/v) to achieve a final concentration of 1 w/v %.

Animals were dosed topically twice daily, five days a week, for 4 weeks.Each dose consisted of 25 micro liters of vehicle control or drug. Thedose was applied to the ventral surfaces of both the right and leftears. All animals were sacrificed approximately 18-24 hours after thefinal dose. The right ears were collected from each animal and used forsebum analysis.

The ears were prepped for HPLC analysis in the following manner. One 8mm distal biopsy punch was taken, just above the anatomical “V” mark inthe ear to normalize the sample area. The punch was pulled apart. Theventral biopsy surface (the area where the topical dose was directlyapplied to the sebaceous glands) was retained for testing and the dorsalsurface of the biopsy punch was discarded.

Tissue samples were blown with N₂ gas and stored at −80° C. undernitrogen until HPLC analysis. In addition to ear samples, an aliquot ofeach drug and vehicle (at least 250 ul) was also stored at −80° C. forinclusion in the HPLC analysis.

HPLC analysis was carried out on an extract of the tissue sample. Tissuesamples were contacted with 3 ml of solvent (a 4:1 admixture of2,2,4-trimethylpentane and isopropyl alcohol). The mixture was shakenfor 15 minutes and stored overnight at room temperature, protected fromlight. The next morning 1 milliliter of water was added to the sampleand shaken for 15 minutes. The sample was then centrifuged atapproximately 1500 rpm for 15 minutes. Two ml of the organic phase (toplayer) was transferred to a glass vial, dried at 37° C., under nitrogen,for approximately 1 hour, and then lyophilized for approximately 48hours. The samples were then removed from the lyophilizer and each vialwas reconstituted with 600 μl of solvent A(trimethylpentane/tetrahydrofuran (99:1). The samples were then recappedand vortexed for 5 minutes.

200 μl of each sample was then transferred to a pre-labeled 200 μl HPLCvial with 200 μL glass inserts. The HPLC vials were placed in theautosampler tray for the Agilent 1100 series HPLC unit. The Agilent 1100HPLC system consisted of a thermostated autosampler, a quarternary pump,a column heater, and an A/D interface module. All components werecontrolled by Agilent ChemStation software. A Waters Spherisorb S3W4.6×100 mm analytical column was maintained at 30° C. by the Agilentcolumn heater unit. The HPLC autosampler was programmed to maintain thesample temperature at 20° C. throughout the run.

10 uL of each sample was injected in triplicate into the column. Twosolvents were used for the solvent gradient. Solvent A was an admixtureof trimethylpentane and tetrahydrofuran (99:1). Solvent B wasethylacetate. The gradient utilized is described in the table below:Time (min) Solv A (%) Solv B (%) Flow (mL/min) 0 99 1 2 2 96 4 2 6 60 402 7 5 95 2 10 5 95 2 10.1 99 1 2

The Sedex 75 Evaporative Light Scattering Detector (ELSD) was operatedat 45° C. with a gain of 5, and N₂ pressure maintained at 3.1 bar.Analog signal obtained by the instrument was sent to the Agilent A/Dinterface module where it was converted to a digital output. Theconversion was based on a 10000 mAU/volt set point and the data rate wasset at 10 Hz (0.03 min). The resulting digital output was then feed intothe Agilent ChemStation software for integration of the peak area.

The results of the HPLC analysis are reported below in Tables IA-C. Theresults are reported as the reduction in cholesterol ester (CE) and waxester (WE) production, when compared to the vehicle control. A negativenumber indicates that the ACAT inhibitor actually increased productionof sebum. TABLE IA Compounds of Invention Change vs. relevant ACATvehicle control Compound Information Inhibition % % Compound (IC 50)Reduction Reduction Sum Number Molecular Structure IAI (nM) in CE in WECE + WE 1

15 94% 80% 174% 1 * (tested multiple times)

15 94% 84% 178% 2

26 65% 31%  96% 3

31 51% 33%  84%

TABLE IB Comparative Examples- Change vs. relevant ACAT vehicle controlCompound Information Inhibition % % Compound (IC 50) Reduction ReductionSum Number Molecular Structure IAI (nM) in CE in WE CE + WE 4

170 −1% −18% −19% 5

61 32%  −4%   28% 6

72 23%  −1%   22% 7

26 −67%   −84% −151%  8

14 −27%   −70% −97%

TABLE IC Change vs. relevant ACAT vehicle control Compound InformationInhibition % % Compound (IC 50) Reduction Reduction Sum Number MolecularStructure IAI (nM) in CE in WE CE + WE 9

44 7% 2% 9% 10

8 −105% −147% −252% 11

8.5 −5% −6% −11% 12

15 48% 44% 92% 13

42 −7% −7% −14% 14

6 −8% −15% −23% 15

3.4 24% 14% 38% 16

26 −1% 0% −1% 17

16 −56% −64% −120% 18

17 −23% −49% −72% 19

12 −6% 1% −5% 20

32 4% −1% 3% 21

45 4% 3% 7% 22

22 20% 4% 24% 23

47 4% −84% −80% 24

11 20% 1% 21% 25

17 10% −3% 7% 26

32 28% 9% 37% 27

35 −17% −23% −40% 28

18 0% −8% −8% 29

48 19% 11% 30% 30

17 −10% −34% −44% 31

43 9% 9% 18%

Tables IA, IB and IC summarize the results obtained in the experimentsdescribed above. Table IA shows the results obtained with compoundsencompassed by Formula I (i.e. the invention). Tables IB and IC areincluded for comparative purposes and include compounds not described byFormula I. Table IB shows diamides structurally related to those ofFormula I. Table IC shows the results obtained with known ACATinhibitors, not structurally related to the diamides, but having an IC₅₀of 50 nm, or less, when measured in the ACAT assay described supra.

To expedite this comparison a common format was used in the threetables. Each compound was assigned an arbitrary compound number, whichis shown in the far left column (i.e. column #1). The second columnshows the structure of the compound tested and the third column showsits potency as an ACAT inhibitor in the assay supra.

Columns 4 through 6 shows the results the compounds had on the secretionof sebum. The results are expressed as the difference from the control.A positive number reflects a decrease in the production of the sebumcomponent being measured, i.e. cholesterol ester(CE) or wax ester(WE). Anegative number indicates that the compound increased the production ofCE or WE.

Column 4 shows the compounds ability to reduce the amount of cholesterolester in the sebum sample. Inhibition of cholesterol ester is importantbecause ACAT is responsible for the conversion of cholesterol tocholesterol ester. These results reflect the compounds ability, or lackthereof, to module ACAT in the target tissue (hamster sebaceous glands).

Column 5 shows the effect the compound had on the generation of waxester. Wax esters are specific markers of the sebaceous glands and arenot appreciably detected in any other layer of the skin. Reduction ofwax ester reflects a decrease in sebum secretion. Columns 6 is asummation of the results expressed in columns 4 and 5 (and is includedto further elucidate relative differences in activity).

As shown in Table IA, the diamides of Formula I significantly decreasedthe secretion of cholesterol ester, indicating that ACAT was beinginhibited in the target tissue. Wax ester was also decreased indicatingthat total sebum secretion was diminished when compared to the control.For example compound #1 decreased CE by 95% and WE by 80%. Compounds 2and 3 produced comparable results.

A comparison with Table IB shows significant differences. Despite thestructural similarity, these diamides had significantly less impact onCE and WE secretion.

A comparison with the compounds of Table IC is also illustrative. Thesecompounds are all potent ACAT inhibitors. All had IC₅₀'s of 50 nm, orless. Despite this potency, as a group, they had significantly lesseffect on sebum secretion than the compound of Formula I. Such resultswere unexpected.

1. A method for alleviating oily skin comprising administering to apatient in need thereof, an effective amount of a compound of theformula:

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or —(CH₂)_(q)-M; pis represented by an integer from 1 to 4; R⁴ is: represented by asubstituent selected from the group consisting of hydrogen, C₁₋₆ alkyl,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alkyl; Ph is represented by a phenylring which may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; or a pharmaceutically acceptable salt thereof.
 2. Amethod according to claim 1 in which said compound is selected from thegroup consisting ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide,andN-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.3. A method according to claim 1, in which said compound isN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,
 4. Atopical pharmaceutical formulation comprising at least onedermatologically acceptable carrier in admixture with an effectiveamount of at least one compound of the formula:

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or —(CH₂)_(q)-M; pis represented by an integer from 1 to 4; R⁴ is represented by asubstituent selected from the group consisting of hydrogen, C₁₋₆ alky,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alkyl; Ph is represented by a phenylring which may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; a pharmaceutically acceptable salt thereof, or aprodrug thereof.
 5. The topical formulation according to claim 6 inwhich said compound is selected from the group consisting ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide,andN-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.6. The topical formulation according to claim 6 in which said compoundis N-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide.
 7. Amethod for decreasing sebum secretion comprising administering to apatient in need thereof, an effective amount of a compound of theformula:

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or —(CH₂)_(q)-M; pis represented by an integer from 1 to 4; R⁴ is represented by asubstituent selected from the group consisting of hydrogen, C₁₋₆ alkyl,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alky; Ph is represented by a phenyl ringwhich may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; or a pharmaceutically acceptable salt thereof.
 8. Amethod according to claim 7 in which said compound is selected from thegroup consisting ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide,andN-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.9. A methodaccording to claim 7 in which said compound isN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide.
 10. Amethod for decreasing sebum secretion comprising administering to apatient in need thereof, an effective amount of a compound of theformula:

in which R³ is represented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or—(CH₂)_(q)-M; R⁴ is represented by a substituent selected from the groupconsisting of hydrogen, C₁₋₆ alkyl, C₁₋₆ alkoxy, halogen, hydroxy,trifluoromethyl, trifluoromethoxy, cyano, NR⁵R⁶, and SR⁷; R⁵, R⁶, andR⁷, are each independently represented by hydrogen or C₁₋₆ alkyl; Ph isrepresented by a phenyl ring which may be optionally substituted; M isrepresented by a 5- or 6-membered heteroaryl ring containing 1hetero-atom selected from the group N, S, or O; and q is represented byan integer from 0-4; or a pharmaceutically acceptable salt thereof. 11.A method according to claim 10 in which said compound is selected fromthe group consisting ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide, andN-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.12. A method according to claim 10 in which said compound isN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide.
 13. Amethod for alleviating acne comprising administering to a patient inneed thereof, an effective amount of a compound of the formula:

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alky, —(CH₂)_(q)-Ph, or —(CH₂)_(q)-M; p isrepresented by an integer from 1 to 4; R⁴ is represented by asubstituent selected from the group consisting of hydrogen, C₁₋₄ alkyl,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alkyl; Ph is represented by a phenylring which may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; or a pharmaceutically acceptable salt thereof.
 14. Amethod according to claim 13 in which said compound is selected from thegroup consisting ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide,N′-[2,6-bis(1-methylethyl)phenyl]-N-(1-methylethyl)-N-[[4-(methylthio)phenyl]methyl]-propanediamide,andN-[2,6-bis(1-methylethyl)phenyl]-]β-[[(4-methoxyphenyl)methyl](2-pyridinyl)amino]-]β-oxo-propanamide.15. A method according to claim 13, in which said compound isN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide.
 16. Anarticle of manufacture comprising a compound of the formula

in which R¹ and R² are each independently represented by hydrogen, C₁₋₆alkyl, C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy,cyano, NR⁵R⁶, or SR⁷; X is represented by —CR⁸R⁹—(CH₂)_(n); R³ isrepresented by hydrogen, C₁₋₆ alkyl, (CH₂)_(q)-Ph, or —(CH₂)_(q)-M; p isrepresented by an integer from 1 to 4; R⁴ is represented by asubstituent selected from the group consisting of hydrogen, C₁₋₆ alkyl,C₁₋₆ alkoxy, halogen, hydroxy, trifluoromethyl, trifluoromethoxy, cyano,NR⁵R⁶, and SR⁷; R⁵, R⁶, R⁷, R⁸, and R⁹ are each independentlyrepresented by hydrogen or C₁₋₆ alkyl; Ph is represented by a phenylring which may be optionally substituted; M is represented by a 5- or6-membered heteroaryl ring containing 1 hetero-atom selected from thegroup N, S, or O; n and q are each independently represented by aninteger from 0-4; or a pharmaceutically acceptable salt thereof,packaged for retail distribution, which advises a consumer how toutilize the compound to alleviate a condition selected from the groupconsisting of acne, oily skin, and seborrheic dermatitis.
 17. Thearticle according to claim 14 in which said compound isN-Benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide.
 18. Amethod for alleviating oily skin comprising administering to a patientin need thereof, an effective amount of a compound of the formula:

in which R³ is represented by hydrogen, C₁₋₆ alkyl, —(CH₂)_(q)-Ph, or—(CH₂)_(q)-M; R⁴ is represented by a substituent selected from the groupconsisting of hydrogen, C₁₋₆ alkyl, C₁₋₆ alkoxy, halogen, hydroxy,trifluoromethyl, trifluoromethoxy, cyano, NR⁵R⁶, and SR⁷; R⁵, R⁶, andR⁷, are each independently represented by hydrogen or C₁₋₆ alkyl; Ph isrepresented by a phenyl ring which may be optionally substituted; M isrepresented by a 5- or 6-membered heteroaryl ring containing 1hetero-atom selected from the group N, S, or O; and q is represented byan integer from 0-4; or a pharmaceutically acceptable salt thereof. 19.A method for decreasing sebum secretion compring the topicaladministration of an effective amount ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide, or apharmaceutically acceptable salt thereof, to a patient in need thereof.20. A method for alleviating oily skin comprising the topicaladministration of an effective amount ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide, or apharmaceutically acceptable salt thereof, to a patient in need thereof.21. A method for treating acne comprising the topical administration ofan effective amount ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide, or apharmaceutically acceptable salt thereof, to a patient in need thereof.22. A method for treating dermal disorders comprising the topicaladministration of an effective amount ofN-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide, or apharmaceutically acceptable salt thereof, to a patient in need thereof.23. A topical pharmaceutical formulation comprising an effective amountof N-benzyl-N′-(2,6-diisopropyl-phenyl)-N-isopropyl-malonamide, or apharmaceutically acceptable salt thereof, in admixture with at least onedermatologically acceptable carrier.